The present invention relates to devices to facilitate coronary bypass surgery.
Heart disease is the leading cause of premature death in humans, both male and female. A prevalent form of such disease is the restriction of arteries at the heart that provide blood to the heart. Blood flow is reduced by atherosclerosis or other disease. A common treatment for such restrictions is coronary artery bypass graft (CABG) surgery.
CABG is usually performed by placing the patient on a heart-lung bypass machine (cardiopulmonary bypass, CPB), cutting off the blood supply to the heart, stopping the heart from beating (cardioplegia) and performing the surgery. The bypass machine supplies oxygenated blood to the body during the surgery. The surgeon makes a long incision down the center of the chest and cuts through the sternum to expose the heart area. The patient is then placed on the heart-lung bypass machine for the surgery which itself requires certain surgical steps to do the attachment. This procedure, even though common, involves certain risks because the heart is stopped and must be restarted and the trauma of connecting the patient to the bypass equipment.
Recently, some surgeons have been using a so-called beating heart CABG procedure which is less invasive than the above described procedure. The beating heart procedure permits the elimination of the use of the heart-lung bypass machine and allows that the heart will continue to beat during surgery. To accomplish the beating heart surgery procedure, a small area of the heart at the site of the bypass graft must be maintained in a non-moving condition while the heart may continues to beat and move normally outside of the surgical site. To make a bypass graft, the blockage is located and points in the artery on opposite sides of the blockage are located. The surgeon will graft a length of vein or artery taken from another part of the body to the blocked artery at the two points on opposite sides of the blockage to bypass the blockage. This procedure is known as anastomosis.
There has been some attempts made to provide a device for stabilizing a portion of the heart. Some of the existing devices utilize vacuum suction and some utilize mechanical force to provide stabilization. One surgical device for stabilizing a heart during heart surgery is disclosed in PCT International Publication No. WO 97/40752, published on Nov. 6, 1997 and which is incorporated herein by reference. There is, however, a need for an improved device for stabilization of the heart that is highly adjustable and provides more effective immobilization of the surgical site.
To be effective, the device needs to control movement of the heart at the surgical site, limiting movement, for example, to less than about 2 mm. The device must also provide the surgeon access to the surgical site. Since the surgery may involve several sites on one patient, the device also needs to be easy to adjust in position in a surgical environment.
Among the several objects and features of the present invention may be noted the provision of a device and a method for stabilizing a localized area of a heart at a surgical site to limit movement of the heart at the site during the surgery, including the beating heart surgery.
One particular object of the present invention is to provide a device which is once positioned and locked in place will have minimal movement, for example, of approximately 2 mm or less.
Another object of the present invention is to provide a series of feet configurations that, once placed, allow for optimal visualization of the anastomosis site.
Yet another object of the present invention is to provide a heart stabilizer that allows a surgeon performing the procedure optimal access to the surgical site.
Still further object of the present invention is to provide a heart stabilizer that naturally opens the artery once an incision is made to assist a surgeon in performing the procedure on the artery.
Still another object of the present invention is to provide a heart stabilizer with a foot having angular wings, suture access areas, tie-downs and a bottom surface texture that optimizes the stability of the foot in contact with heart tissue.
Further objects of the present invention are provision of such a device that is easy to adjust yet can be locked firmly in place; the provision of such a device that has a heart engaging foot, at least one arm, and a locking mechanism that will retain the arm and the foot of the stabilizer in position even when the locking joint is loosened to adjust the position of the heart engaging foot.
Additional objects of the present invention are to provide a device that has a reusable and disposable parts and which is easy to use by a surgeon in beating heart CABG procedures and the provision of such a device that can be used with a variety of chest spreaders.
Yet further object of the invention is the provision of a device that allows for a wide variety of foot mounting positions to accommodate optimal access to arteries in all various surgical sites on the heart.
All other objects and features of the present invention will be apparent from the detailed description of the invention.
In one aspect of the present invention, a foot for use with a heart stabilizing device for engaging a portion of a heart during a medical procedure is provided. The foot of the present invention comprises two laterally spaced apart fingers, said fingers each having an inner edge with said edges defining a surgical site therebetween, each finger having a bottom surface, each said bottom surface having an angled surface portion extending upwardly and away from the inner edge. Preferably, an included angle between the angled surface portions is in the range of between about 110xc2x0 and about 160xc2x0 and, even more preferably, in the range of between about 120xc2x0 and 140xc2x0. A bridge is secured to and extends between the fingers adjacent an end of each finger. A mounting post is secured to the bridge and extends therefrom. The foot of the present invention may be used with a variety of known stabilizers, and may be attached, for example, to a support structure consisting of two arms adjustably connected to each other. The foot of the present invention may be disposable or reusable.
In another aspect of the present invention, a stabilizing device is provided that includes a locking mechanism that allows for selective locking of the different parts or elements of the device relative to each other. The locking is such that when the locking mechanism is in a locked position, the elements are fixed relative to each other, but if the locking mechanism is in an unlocked position, the elements of the device are still maintained substantially in position relative to one another until moved by an operator. The locking mechanism of the device of the present invention may have frictional resistance to the relative movement of the elements and such resistance is created by a pre-load. The examplary elements of the surgical device for stabilizing cardiac tissue are a foot and one or more elongate arms.
In one examplary embodiment, such pre-load locking mechanism movably connects two arms of the surgical device of the present invention. The device comprises first and second elongate arms and a joint with said first and second arms mounted thereon for selective multiaxis movement of the first and second arms relative to one another. The device also has lock means with a locked position for selectively locking the first and second arms in a selected position relative to one another, and an unlocked position wherein the joint is operable to maintain the first and second arms substantially in position until moved by an operator.
Alternatively, the described locking mechanism may be used only for a movable connection and selective locking between the foot of the stabilizer and one of the arms of the device. Similarly, the above-mentioned locking mechanism may be used for a movable connection and selective locking between one arm of the device and a chest spreader to which such arm is mounted. If desired, in some embodiments, any two or all three of the above-described elements of the device may use the locking mechanism that allows to maintain the elements substantially in position relative to one another until moved by an operator even when the locking mechanism is in the unlocked position.
In an additional aspect of the present invention, a stabilizing device is provided that uses an arm comprising of two portions: a rigid portion and a flexible articulated portion. The articulated arm of the present invention allows for multi-axis movement, including an axial (or sliding), rotational and pivotal movement of the rigid and the articulated portions that improve adjustability of the device of the present invention. The articulated arm includes a locking mechanism operable to secure the articulated portion in a desired configuration.
Yet in another aspect of the present invention a stabilizing device includes a foot connected to a support structure wherein the support structure includes at least one arm pivotally mounted on a base for connection to a fixed object, such as a chest spreader. Such arm is being pivotally movable on the base in substantially only one plane.
A further aspect of the present of the present invention involves the provision of a method of performing heart surgery. The method includes a step of obtaining a device for isolating and stabilizing cardiac tissue comprising a stabilizing foot having at least two heart engaging bottom surfaces which are inwardly angled relative to each other. Then placing the angled heart engaging bottom surfaces on opposite sides of the surgical site; applying force to the heart through the angled bottom surfaces to stretch and stabilize the portion of the heart at the surgical site; and finally, performing a medical procedure on the cardiac tissue at the surgical site.
Other objects and features will be in part apparent and in part pointed out in the detailed description of the invention.